In-situ experiments at SNBL using high gas pressures (report)


A proper understanding of structure-property relationships plays a central role in the design and discovery of novel materials.
In many cases, developing the relationship between the structure of a new material and its physical and chemical properties requires
that measurements be made under exactly the same in-situ conditions of temperature, pressure and atmosphere that match the performance
environments of the materials of interest. Examples of research at SNBL leading to a better understanding of materials properties already
include catalysis, battery and fuel-cell studies, and solid-state hydrogen storage technology.

Our goal is to develop apparatus for high gas pressure experiments which will enable us to follow gas-solid chemical reactions in-situ
using various x-ray methods. The experiments will often be carried out in conjunction with other techniques such as Raman or optical
absorption spectroscopy. In addition to the dependence upon gas pressure, we may also wish to vary other experimental parameters
such as temperature, humidity, gas-mixture, flow-rate etc. Further information may be obtained by monitoring the gas products using analytical
tools such as mass spectrometry. Various X-ray methods including powder and single crystal diffraction, small angle scattering and x-ray
absorption spectroscopy may be employed, either separately or in different combinations.

It is evident that an individual cell design will not be able to accommodate all of this wealth of experimental techniques, particularly
when we take into account the wide range of gas pressures which we wish to cover (10 bar - 700 bar). In addition, the use of high gas pressures
combined possibly with high temperatures and the presence of gas mixtures poses serious challenges for the safe operation of our equipment.
Finally, the experiments must be operated remotely, with no manual access to the equipment during data collection.
This implies that, as far as possible, we must ensure full automation of the apparatus from the start to the end of the experiment.

We now need to set certain priorities concerning the type of cell (or cells) to use for our in-situ experiments, together with the gas supply set-up
(including possibly a gas-mix rig), and the compressor system necessary in order to reach the high pressures. To assist the SNBL team in defining
the specification for our reaction cells and associated high pressure equipment, we are holding a two-day workshop at the ESRF
on 8 - 9 November 2007 (program).
All SNBL users who might be interested in the use of this type of equipment are encouraged to take part in this workshop, so that each group
can ensure that their input will be properly taken into account. We are also seeking suggestions concerning possible speakers for this meeting.
Note that the meeting is being organized together with our colleagues from the Dutch/Belgian beamline.
Further information will appear in due course on our SNBL web site.


A provisional list of speakers and their topics is given below:

Paul Barnes (Birkbeck / University College London)
Structure and dynamics of functional materials / cement hydration / hydrothermal crystallization

Philip L. Llewellyn (Université de Provence - CNRS, Marseille)
In-situ diffraction experiments, gas/solid reactions in metal-organic framework structures

Andrew M. Beale (Dept of Inorganic Chemistry and Catalysis, Utrecht)
In-situ catalysis / combined UV-Vis, Raman and XAFS

Olga Safonova (SNBL)
Apparatus for in-situ catalysis experiments

Wim Bras (DUBBLE)
Combining SAXS, WAXS and EXAFS for investigating hydrothermal crystallization processes